Bancroft



7 Sheets-Sheet 1.

(No Model.)

- J. S. BANOROFT.

TOOL GRINDING MACHINE. No. 460,497. Patented Sept. 29, 1891.

WITNESSES.-

(No Model.) 7 Sheets-Sheet 2.

v J. S. BANGROPT.

TOOL GRINDING MACHINE. No. 460,497. Patented Sept. 29, 1891.

IIVI/E/VTOYR W/T/VESSES Tu: norms PETERS ca. PHorlrumm, WASHINGTUN, n.c.

7 Sheets-Sheet 3.

(No Model.)

J S BANGROFT TOOL GRINDING MACHINE.

WITNESSES:

(No Model.) I 7 Sheets--Sheet 4.

J. S. BANGROFT.

TOOL GRINDING MACHINE.

No. 460,497. Patented Sept. 29, 1891.

W/ T/VESSES l/WE/VTOR 9.5% iv/ f?nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn c.

(No Model.) 7 Sheets-Sheet 5.

J. S. BANGROFT. TOOL GRINDING MACHINE.

No. 460,497. Patented Sept. 29, 1891.

FIG. 8;

W/ Til E8858 (No Model.) 7 Sheets-Sheet 6.

J. S. BANCROFT.

TOOL GRINDING MACHINE. v No. 460,497. Patented Sept. 29, 1891.

WITNESSES I/VVE/VTOH NITED STATES PATENT OFFICE.

JOHN SELLERS BANOROFT, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TOIVILLIAM SELLERS 8; COMPANY, INCORPORATED, OF SAME PLACE.

TOOL-GRINDING MACHINE.

SPECIFICATION forming part of Letters Patent No. 460,497, datedSeptember 29, 1891.

Original application filed May 12, 1887, Serial No. 237,986. Divided andthis application filed November 15, 1889. Serial No. 330,460. (Nomodel.)

To all whom Lt may concern:

Be it known that I, JOHN SELLERS BAN- CROFT, of the city and countyofPhiladelphia, and State of Pennsylvania, have invented certain new anduseful Improvements in 'lool-Grinding Machines, of which improve mentsthe following is a specification.

My invention relates to a device for forming by grinding the curvedfaces and cuttingxo edges of cutting-tools used on machine-tools.

In order to produce the best output from machine-tools in the twoessentials of quality and quantity, the shape of the cutting-tools whichremove the material is an exceedingly important factor. In most shopsthe shapes of these tools have been and are left to the udgment of theindividual operator, with the result that few, if any, tools in suchshops are made in the best shapes.

It is an object of my present invention to provide means for rapidly andeconomically forming by grinding the working faces of metal-cuttingtools.

It is a further object of my invention to provide means whereby thesefaces can be accurately formed and located with reference to each otherand to the shank of the tool.

It is a further object of my invention to provide means whereby anexisting tool can 0 be used to produce a record of its shape,

which record will enable the operator to produce similar tools; and tothese ends my invention consists in providing an oscillatingtool-holding chuck in which the tool to be 5 ground may be held with itsshank approximately at right angles to the axis of oscillation, and inso arranging the supporting-bearing for this chuck that it may be set atany desired angle with a tangent plane of the 40 grinding-wheel and inmounting this bearing upon two sliderests at right angles with eachother, whereby cylindrical or conical surfaces may be produced upon atool held in the chuck; and it further consists n provid ng meanswhereby the axis of this oscillating chuck may have a vibrating motionto and from the wheel for the purpose of varying the contour of thetool; and it further consists in providing this oscillating chuck with aformer-plate, which determines the amount and relation of the vibratingmovement; and it further consists in providing means for altering therelative positions of the formerplate and .the shank of the tool to beground, whereby the relative position of the curved cutting-edge of thetool to its shank may be varied, as required; and it further consists inproviding a movable indicator by which the position of the tool to beground may be de termined relatively to the axis of the oscillat- 6o ingchuck; and it further consists in so arranging this movable indicatorthat the position and relation of the tool to be ground can bedetermined with reference to the formerpla'te; and it further consistsin providing an indicator which is moved in one direction by the tool tobe ground and in the opposite direction by gravity or a spring; and itfurther consists in providing this indicator with an index and suitablegraduations by which the size of: the tool may be measured, either inradial distance from the axis of the chuck or relatively to theformer-plate, whereby tools of varying sizes and outlines can be formedfrom the same former-plate; and it further consistsin providing means bywhich acurvedface tool can be used as a templet to control the vibratingmotion of the oscillating chuck, whereby a former-plate can be ground tothe proper contour for reproducing similar tools. In the accompanyingdrawings, which form part of this specification, Figure 1, Sheet 1,represents a side elevation, partly in section, of one form of mypresent invention shown as mounted upon the slide-rest E, described andshown in my application filed May 12,

1887,'Serial No. 237,986, of which this application is a division. Fig.2, Sheet 2, is ahorizontal section through the axis of the oscillatingchuck shown in Fig. 1. Fig. 3, Sheet 0 3, is an end elevation showing atool in place to be ground, with the former-plate, abutment, andindicator. Fig. 4, Sheet 1, is a sectional elevation of the former-plateand part of the oscillating chuck which carries it, taken on the line 3s of Fig. 2. Fig. 5 is an end view, partly in section, on the line ttofFig.2, of part of the apparatus for altering the relative position ofthe former-plate and the shank of the tool. Fig. 6, Sheet 2, showsthehand-leverby I00 which the parts are adjusted and secured. Fig. 7,Sheet 4, is a horizontal section through the axis of the oscillatingchuck when arranged to be inserted in an adjustable rotatable chuckarranged with a vibrating movement. This is the form I prefer, wherebyone machine is made capable of grinding all forms of tools. Fig. 8,Sheet 5, is a horizontal section through the front end of theoscillating chuck shown in Fig. 7, with the parts in place ready togrind a former-plate to conform to a finished tool. Fig. 9 is an endelevation of the same parts. Fig. 10, Sheet 6, is a perspective View ofthe oscillating tool-holding chuck mounted in its vibratin g bearingcarried by the supporting-bearing, with the indicator in position foradjusting a tool to place, indicating by broken lines the position ofthe grinding-wheel. Fig. 11, Sheet 7, is a side elevation of the stand'1, shown in Figs. 8 and 9. Fig. 12 is a view of part of the adjustablebearing with the counter-weight and connections. Fig. 13 is a sectionthrough Fig. 12 on the line 1 'y, showing the indicator-stand inosition. Fig. 14 is a plan of the indicator. In all the figures similarletters and numerals refer to similar parts.

The supporting-bearing Nis shown in Figs. 1 and 2 in position upon theslide-rests E and E, described in adivision of this application. It isprovided with a bearing to fit on the pin 9, about which it swivels, andwith a clamping-bolt m, by which it is secured at the proper angle togive the desired clearance to the tool. It is provided with a fixedindex and vernier 9t, adjoining the flange 'n, and when this indexcoincides with the ninetydegree point of the graduations on the flange'n the horizontal axis of the oscillating chuck is parallel with thetangent plane of the abradingsurfaee of the grinding-wheel.

A tool S, with curved face, is shown in Figs. 2, 3, 7, and 10 as securedin position in the clamping-jaw L of the oscillating chuck, the jaw Lbeing formed with or secured adjustably or otherwise to a journal 0,turning freely within the vibrating bearing D ,the axis of the journalbeing the axis about which the oscillating chuck oscillates. Thisjournal is provided with a flange 17 and on the other end with a collaror nut 18, which together preventall end motion. The flange 17 isformed, as indicated in Fig. 1, so as to provide a seat for the severalformer-plates required, 19 being a representation of one of them. Oneedge 20 20 of the former-plate is made straight, with a rectangularnotchor recess 21 formed in it, as shown in Fig. 4, the

straight edge and recess fitting a corresponding straight edge andtongue formed 011 the flange 17. By this arrangement the formerplatesare accurately and securely located with reference to the axis of theoscillating chuck, while at the same time they can readily be removedand replaced.

The former-plate 19 is shown as resting against an abutment, which Iprefer to make in the form of a roller 22, in order to reduce thefriction. This roller 22 is carried by and revolves freely on the stud23, secured in the stand P, which is provided with two bolts 24: 25,which engage with the slots 2 1 and 25, (see Fig. 12,) and thus secureit to the adjustable supporting-bearing in the same manner as the standT, which replaces it, as shown in Figs. 8 and 9. The vibrating bearing Dis pivoted on or swung from the shaft II, secured in the upper part ofthe arch in the adjustable bearing N. By swinging the hearing D the axisof the journal 0, which is the axis of the oscillating chuck, isvibrated toward and from the grinding-wheel in a path which isdetermined by the distance from the shaft H to the axis of the journal0.

The counterweight-lever I, pivoted at 5 in the supporting-bearingN, (seeFig. 12,) is provided with a pin 1 and block 6, which engage with a slot7, formed in an arm of the vibrating bearing D, and by which the bearingD is forced toward the right, as shown in Fig. 3, and by which pressurethe former-plate 19 is pressed against the abutment-roller 22. Thefunction of the counter-weight is to hold the former-plate against theabutment with sufficient force to insure the vibrating motion of thechuck, and provided this result is accomplished the counter-weight maybe arranged in any desired way. By properly proportioning its weight andposition it may be rigidly secured to the vibrating bearing D. (See 35,Fig. 9.) The former-plate 19 is made of such size that when it restsagainst the roller 22 the vibrating bearing D can at no time strikeagainst either side of the arch on the bearing N, which supports it, andhence the former-plate 19 will be held to its seatin the flange 17 andagainst the roller 22 by a force due to the weight of the counter-weight35 multiplied by the leverage through which it acts.

The jaw L is shown in Figs. 2 and 3 as resting upon a pin 36, whichslides freely in and is guided by a bearing 37, formed with or securedto the adjustable bearing N. This pin 36 serves to support the jaw L ina horizontal position for greater convenience in placing or removing thetool. During the operation of grinding the pin 36 is drawn back,allowing the jaw L of the oscillating chuck to oscillate freely aboutits axis in the vibrating bearing D to the extent of about one hundredand eighty degrees, as may be required for presenting the contour of thetool held in the chuck to the abrading-surface e of the grindingwheel.If the curved shape of the formerplate is circular, with its centercoinciding with the axis of the oscillating chuck, there will be novibrating motion of the axis to and from the grinding-wheel as the chuckis oscillated, and the motion and the shape produced will be the same asthough the former were removed and the vibrating bearing D restedagainst the side of the arch of the adjustable bearing N, or as thoughthe oscillating chuck were j ournaled directly in the bearing N, and thecontour produced upon the tool held in the jaw L would be circular, theaxis coinciding with the axis of the oscillating chuck and the radiusdepending upon the distance that the end of the tool projects beyondthis axis toward the grinding-wheel. If the former is of any shape otherthan circularas,- for example, as shown in Fig. 3-. then as the chuck isoscillated about its axis the former-plate 19, acting in one directionand the counter-weight in the opposite direction, will cause the bearingD, and with it the axis of the oscillating chuck, to vibrate to and fromthe abrading'surface e of the grinding-wheel to the extent of theeccentricity of the former-plate, and a tool S, held in the oscillatingchuck, would be ground to a shape parallel to the contour of theformer-plate, and its size or the distance between these two parallelcurves can be measured by the movable indicator hereinafter described.As the grinding-wheel and the abutment-roller 22 are both on the sameside of the axis of the oscillating chuck, it follows that in grinding atool in this chuck, the pressure of the formerplate against the roller22 is diminished by the amount of the pressure of the tool against thegrinding-wheel, and that this latter pressure cannot exceed that due tothe counterweight 35 multiplied by the leverage through which it acts.By adjusting either the weight of this counter-weight or the leveragethrough which it acts the maximum pressure which can be exerted on thetool can be determined and limited.

For the purpose of determiningthe distance that a tool S should projectbeyond the axis of the oscillating chuck when clamped in its jaw L, Iprovide the movable indicator R. (Shown in position as against the endof the tool in Figs. 1, 3, l0, l3, and 14, the part which bears againstthe tool being curved to correspond with the averagecurvature of theabrading-surfaceof thegrinding-wh'eel.) Theindicator R is secured to theshaft 38, which turns and slides freelyin the bearings 39 and 40 in thestand P. (See Figs. 1, 3, 10, 13, and 14.) A weighted lever 42, pivoterlon the stud 43, secured in the stand P, is provided with an arm 44,which rests against the hub 45 of the movable indicator R. The weight ofthe lever 42 is sufficient to slide the shaft 38 through its bearings,and so presses the indicator R against the "end of the tool S. The lever42 has an index 46, which moves along a graduated are 47 on the stand P,concentric with the pivot 43, and as the tool S is pushed forward in thejaw L the index 'rises, and when the proper graduation is reached,sufficient allowance being made for the amount of metal to be removed bygrinding, the toolis clamped fast in the jaw L and the movable indicatorswung up out of the way into the position shown by the broken line inFig. 1 at R.

.Before removing the tool from the chuck thus enable the operator togrind the tool to the desired size without any other gage than isafforded by the indicator.

In the foregoing description the jaw L of the oscillating chuck has beendescribed as though it was formed with or rigidly secured to its journal0, turning in the bearing D, and for many purposes such an arrangementwould be sufficient. To adapt the machine, however, to more general useand to reduce the number of former-plates required and the time ofchanging them and of grinding unnecessary material from certain tools, Iprefer to attach the jaw Ladjustably to the journal 0, whereby a benttool may be ground with the same facility as a straight one and with thesame former, and any tool held in the jaw L may be moved transversely tothe axis of the chuck to equalize the amount of metal to be removed fromits two sides. To grind the bent tool above referred to, the chuck-j awL has a pivoted connection with the coverplate 52, firmly secured to theslide-rest 53, and for this purpose is provided near its forward endwith a pivot-pin 51, which fits into and turns easily in a bearingprovided in the cover-plate 52. The jaw L is provided with a bolt 54,which passes through a curved slot in the slide-rest 53 and serves tosecure the jaw L firmly to the slide-rest 53 when it has been adjustedto the proper angle for the shank of the tool, as determined bygraduations provided on the end face 56 of the sliderest 53. Theslide-rest 53 has firmly secured in it the pin 50, which slides in andis guided by the bearings 48 and 49, formed on the flange 17 of thejournal 0, whereby the slide-rest can be moved in a plane at rightangles to the axis of the oscillating chuck between the bearings 48 and49 without changing the angle at which the jawL may be secured. Theslide-rest 53 may be pivoted to an extension of the flange 17, so as toswing across in an arc of a circle, instead of sliding in a straightline. I have constructed the slide-rest in this way, but prefer themethod shown, as making no change in the angle of the toolsh'ank inadjusting. A locking-bolt57 passes freely through a hole bored throughthe journal 0 and the countersunk slot 58 in the slide-rest 53 and isprovided at one end with a head 59, which engages in this slot 58 and bywhich the slide-rest 53 may be firmly secured to the flange 17, whendesired. A part of the periphery of this head 59 is provided with teeth,as shown in Fig. 5, which IIO engage with corresponding rack-teeth inthe slide-rest 53,whereby rotation of the lockingbolt 57 will move theslide-rest between the bearings 48 and 49 and end movement of the boltwill clamp the slide-rest firmly to place. On the other end of the bolt57 is keyed, so as to turn with it, the fulcrum-block 60,which isprovided with two trunnions 61 and 62, which carry the adjusting-lever63. This is made in three pieces, as indicated in Fig. 6, forconvenience in manufacture, and the holes in the two side plates whichfit on the trunnions 61 and 02 are eccentric to the rounded ends of theside plates. The block 60 is adjusted to position on the locking-bolt 57by the lock-nuts 64:, and when the lever (53 is in the position shown inFig. 2 the locking-bolt 57 is perfectly free and may be rotated and theslide-rest 53 adjusted up or down by the rack and pinion by moving thelever 63 up or down, which movement turns the fulcrunrblock 60 and withit the locking bolt 57. \Vhen the slide-rest is in the desired position,the lever 63 is swung on the trunnions 01 and 62 in a plane at rightangles to the adjusting movement, so as to bring it more into line withthe bolt 57, as shown in brokenlines in Fig. 2. This movement forces theeccentric ends of the side plates of the lever 63 against the end of thejournal 0 or the nut 18, which transmits the pressure to the journal 0and thus draws the bolt 57 back until the slide-rest 53 is, by means ofthe head 59, firmly clamped against the enlarged end of the journal 0.The slide-rest 53 also covers part of the former plate 19,which is madeslightly thicker than the depth of the seat provided for it in theflange 17, so that the operation of clamping the slide-rest also clampsthe formerplate. The coverplate 52, which carries the pivot of the jawL, is secured firmly to the slide-rest 53 and serves, also, to protectthe rack-and-pinion adjustment of the slide-rest from grit and water andas a stop to support the indicator R at the proper height for measuring.(See Fig. 1.)

The operation of adjusting a tool to be ground in this form of theoscillating-chuck is as follows: A tool S, Fig. 3, is laid on the jaw Lin the position shown, if its shank is straight. If the shank is benteither right or left hand, as indicated by the broken lines, the jaw Lis adjusted and clamped by the bolt 54 to the proper angle in theslide-rest 53. It will be noticed that the end of the tool to be groundbears the same relation to the former-plate 19, whether its shank isstraight or bent. The tool is now pushed forward in the jaw L, theindicator B being in position, as shown, until the index at indicatesthe proper figure for a tool of the given size and shape, as noted in atable giving the settings for the various tools the machine is requiredto grind. It is then secured in the jaw L by the set-screws ff, the pin36 is withdrawn, and the jaw L, carrying the tool S, is oscillated aboutthe axis of the journal 0 by the handle K, the indicator R stillbearin gagainst the tool. If when the handle K is in its highest and lowestposition the reading of the indicator is nearly alike, the tool isproperly adj usted and may at once be ground. If, how ever, the readingsin the highest and lowest positions vary considerably,then the operator,taking the adj Listing-lever 63in his left hand, moves it so as torelease the slide-rest 53 and then swings it about the axis of thechuck, so as to move theslide-rest into such a position that the readingof the indicator is as nearly equal as possible in all posit-ions of thechuck, when the adj Listing-lever 63 is moved so as to reclamp theslide-rest 53. After the tool has been ground the indicator should beused to show whether the end has been reduced to the proper size. Theclearance of the toolthat is, the angle which any element of the curvedsurface makes with a line perpendicular to the base of the tool-isobtained by setting the supporting-bearing N at the desired angle, asindicated by the index a. As the shape produced on the tool is parallelto the curved outline of the former-plate, it is possible to vary theshape as well as the size of the tool by using a formerplate ellipticalin outline, having its focus between the axis of the chuck and theperiphery of the former. Then if the end of a tool is at this focus itwill be ground to a sharp point, and by Varying the distance that thetool projects beyond this focus the radius of ourvature of the end ofthe tool may be varied to any desired extent. The contour of the toolwill be exactly parallel to the curve of the former plate only when thepoints of tangency of the plate and roller and of the tool andgrinding-wheel are in the same plane with the axes of thegrinding-wheel, the roller, and the oscillating chuck. If there is muchdifference in the radii of the roller and grinding-wheel, together withlarge eccentricity in the former-plate, then the point of tangency willnot remain in the same plane and the curve will not be exactly parallel.

In the oscillating chuck hereinbefore shown and described the adjustablebearing N has been described as fitting on the slide-rest E. (Shown in adivision of this application, Serial No. 237,986, filed May 12, 1887,and taking the place of the adjustable supportingbearing therein shownand described.) It is not necessary, however, that the machine on whichthis oscillating chuck is used should be provided with a verticalslide-rest, neither is it essential that the grinding-wheel should be ofthe double conical form therein shown and described, for as this chuckis for the purpose of grinding curved outlines only it may be used witha plain cylindrical wheel,

and the grinding may be done on the face or the side of the wheel, asmay be found most convenient. The construction I prefer is shown in plansection in Fig. 7, the vibrating bearing D being enlarged, so as toreceive the rotatable tool-holding chuck D, provided withclamping-screws and index and graduations and adapted to receive andhold tools the cutting-edges of which are formed bythe lntersection ofplane surfaces, as described and shown in my application, Serial No.237,986, of which this is a division, and it is also capable ofreceiving the sleeve M, which is a bearing for the journal 0 of theoscillating chuck hereinbefore shown and described. In this arrangementthe rotatable tool-holding chuck is capable of receiving-a vibratingmotion to and from the grinding-wheel, and either plane or curved facedtools may be ground by removing or inserting the bearing M, with itsattached parts. When the shape of a tool has been determined byexperiment for any particular case, it is desirable to be able to recordand reproduce this shape. Suppose the tool S, Fig. 3, to be a tool toberecorded. Then if the indicatorR be clamped to place so as not toslide back and forth and an emery-wheel be put in the place of theroller 22 it will be clear that as the chuck is oscillated the tool S,bearing against the indicator, will cause the chuck to vibrate to andfromthe grinding-wheel, and the former-plate 19 would be ground tocorrespond with the shape of the tool S.

By reference to Figs. 2 and '7 it will be seen that by removing theroller 22 the former 19 could be brought into position by the sliderests to be ground by the grinding-wheel A. This method would, however,require the indicator to be made heavier than would be necessary orconvenient for ordinary use, and I therefore provide for this purposethe stand T, Figs. 8, 9, and 11, which is secured to thesupporting-bearing N in the same manner and at the same bearing-pointsas the stand P, which is removed for this purpose. A movableabutment-plate 65, secured to the arm of the stand T, takes the place ofthe indicator R, as above described, and to have more room to grind theformer-plate blank 68 it is secured to a block 69. (Shown as clamped bythe slide-rest 53 in the same, seating as is provided for theformer-plate 19.) This block merelyserves to hold the former-plate blankin a more convenient position relatively to the grindingwheel without inany way changing its relation to the axis of oscillation of the chuck orthe tool to be recorded. WVhen the formerplate blank is ground to shape,the block 69 is removed and the finished former-plate put in the seatprovided in the flange 17. The stand T is removed and the stand P,carrying the indicator R, replaced, and the reading of the index 46 isthen taken and recorded, and a duplicate tool can then be made at anytime which will be precisely similar to the sample, or tools larger orsmaller can be made by varying the reading.

Having now described my invention, what I claim as new, and desire tosecure by Letters Patent, is

1. In a tool-grinding machine, an oscillating tool-holding chuck mountedupon a bearing tool-holding chuck adapted to receive a vibrating motionto and from an abradingsurface of a grinding-wheel, a supportingbearingadjustable about an axis at right angles to the axis of oscillation, andan abutment, in combination with a former-plate which determines theamount and relation of the vibrating movement of the chuck.

4. In a tool-grinding machine, an oscillating tool-holding chuck, avibrating bearing, and a former-plate with its abutment, in combinationwith a slide-rest, which determines the distance between the axis ofoscillation and the shank of a tool or of the former-plate.

5, In a tool-grinding machine, an oscillating tool-holding chuck, avibrating bearing, an abutment, a former-plate, and a slide-rest foradjusting the relative position of the tool and the former-plate, incombination with a locking-bolt coupled to the slide-rest.

6. In a tool-grinding machine, an oscillating tool-holding chuck, avibrating bearing, a former-plate withits abutment, and a sliderestprovided with a rack, in combination with a locking-bolt provided with atoothed head. I

7. In a tool-grinding machine, an oscillating tool-holding chuck, avibrating bearing, an abutment, a former-plate, a slide-rest, and alocking-bolt, in combination with an adj usting-lever.

8.'In a tool grinding machine, an oscillating tool-holding chuck, avibrating bearing, a former-plate carried by the chuck, and an abutment,in combination with a pivoted connection between the chuck jaw and theformer-plate.

9. In a tool-grinding machine, an oscillating tool-holding chuck, avibrating bearing, and a' supporting-bearing, in combination with acounterweighted lever pivoted to the supporting-bearing and connected tothe vibrating bearing of the oscillating chuck.

10. In a tool-grinding machine, an oscillating tool-holding chuck, incombination with a movable indicator.

11. In a tool-grinding machine, an oscillating tool-holding chuck, aslide-rest, and a former-plate, in combination with a movable indicator.7

12. In a tool-grinding machine, a tool-holding chuck, in combinationwith an indicator tool to be copied, in combination with an which ismovable into contact with the surabutment. face upon which the grindin-whcel is to opcrate or has operated. a SELLERS LANCROFT' 5 13. In atool-grinding machine, a vibrating \Vitnesscs:

bearing and an oscillating tool-holding chuck HORACE A. SELLERS, adaptedto hold ablank former-plate and the JOHN L. PHILLIPS.

